Automatically-operated switch.



CARL WILLIAM EISENMANN, OF CHICAGO, ILLINOIS.

AUTOMATICALLY-OPERATED SWITCH.

Specification of Letters Patent.

Patented Aug. 11, 1914.

Application filed July 1, 1912. Serial No. 706,935.

To all whom it may concern:

Be it known thatI, CARL W. EISENMANN, a subject of the German'Einpire, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Automatically- Operated Switches, of which the following is a full, clear, and exact specification.

T is invent-ion relates to improvements in automatically operated switch systems for making and breaking the circuit between a dynamo and a storage battery, in electric systems generally, but more specifically for railway cars, in which the switch contacts are mounted on a movable member actuated by electro-magnets, and on the demagnetization of which magnets the gravity of the movable member, moves the switch to an open position, and is alone the sole means for maintaining the switch in its open position. In practice it is found that in the presence of the rough handling of trains or their leaving the rails, the force of this gravity of the lever is not sufficientto prevent the frequent accidental closing of the switch, which is also not infrequently closed by the unintentional physical contact of the train crew and others, with the lever, with the result that the dynamo being inactive or its voltage lower than the operative voltage of the battery, the latter is discharged orthe fuse burned out, or connections fused and destroyed. In other words, whenever, or if under any circumstances the circuit between a dynamo and a storage battery is closed at a'time when the voltage of the battery is greater than that of the dynamo, the battery will be discharged, the fuse burned out and possibly the whole lighting system will be put out of commission, and it is to prevent the accidental occurrence of this result to which my invention is directed.

The object of my invention broadly stated, is to provide a means, automatically operating, to prevent the closing of the switch between a storage battery and a dynamo, at any time when the voltage of the dynamo 15 less than that of the battery, and until the voltage of the dynamo is equal to or exceeds that of the operative voltage of the battery.

More specifically stated, the Ob]ect of my invention is to provide an automatlcall electrically operated means which, 'in addition to the gravity of a movable support for the contacts of the switch for opening and closing the circuit between the battery and a dynamo, furnishes t0 the said movable support a force maintaining the switch open in the presence of jars from a running train, its sudden stoppage and physical contact with the member which, otherwise, would move the contact to a position accidentally closing the circuit.

With these ends in view, my invention finds embodiment in certain features of novand voltage commonly employed in railway cars and other electric light systems, which battery is connected with the positive side of lamps 3 by wire 4, a wire 5 connecting the battery with the negative side of said lamps, and the dynamo 6 through brush 7. The negative brush 7 of the dynamo is connected to the shunt dynamo field 8 by the wire 9; to the negative side of the battery by wire 5; and to the negative side of the lamp circuit 3 by wire 9. The switch 10-l1 is obviously for the purpose of connecting and disconnecting the lamps from the dynamo and battery. The positive side of the dynamo is in circuit with one terminal of a coarse retaining winding 12, on the cores 13 and 14 of an electro-magnet by means of wire 15, the other terminal of this winding being connected by a wire 16 with a switch block 17. The dynamo is also in shunt circuit with the fine wire lifting coils 18 on the poles 13 and 14 of a magnet, by means of a wire 19 for one terminal, and 20 for the other terminal thereof.

Pivoted at one end to a fixed bracket 21 is a lever 22 on the opposite and free end of which are supported contact fingers 23 and 24 respectively opposite contact post 17, and contact post 25, the contact post 25 being connected with the positive side of the battery by wire 26, connected as it is shown with wire 4, contact post 17 being connected with the positive side of the dynamoby wire 16. The lever 22 is held in contact with the magnet above referred to, and the switch closed so long as the voltage oi the dynamo is equal to or above that of the operative voltage of the battery. When, however, the voltage of the dynamo becomes less than that of the operative voltage of the battery, then the lever by gravity releases itself from the magnet, and thereby opens the switch, when, and so long as the voltage of the dynamo equals or is above the operative voltage of the battery, the e wire coils will be energized suficiently to lift the lever to contact with the magnet when the subsequent force following the energizing of the coarse wires will retain the lever to contact with the magnet and the switch closed. For the purposes above described, it should here be noted that there are more turns of the fine wires in the lifting coil than in the heavier wires of the retaining coil of the magnet.

Every feature and operation of the structure so far described is old, and subject to the objection that with the lever out of contact with the magnets, and the switch open there is no force, other than the gravity alone of the-lever, to' prevent jars transmitted from a moving train, or its sudden stopping or an inadvertent slightly lifting physical contact with the free end of the lever from lifting the lever, suficient to close the switch, and as a result discharge the battery and burn out the fuse, and thereby put the lamp or dynamo system, or both, out of commission, if and when at that time the dynamo is inoperative or has lower voltage then the operating voltage of the battery. To overcome, and ,thereby entirely avoid so far as is possible with automatically operating means, this very serious objection in operation from any of the causes above enumerated, my invention finds embodiment in the employment of a holding magnet, the poles of which are 27 and 28, immediately below the lever 22, and if desired respectively in alinement with the magnets 13 and 14. The electromagnet poles 27 and 28 are provided with, and energized, by means of fine wire coils 29 and 30, the terminals of which, 31 and 32, are respectively connected with the'positive side of the dynamo by means of the wire 20, and with the positive wire 4 of the battery, by means of the wire 32, and, therefore, constantly in circuit with the battery, throu h the field and armature of the dynamo, so ong as the switch is open, but are demagnetized by the closin of the switch, or by the current from the ynamo, when its voltage is at or above that of the battery. en the dynamo and battery voltage are equal the difi'erence in voltage at terminals of this holding magnet is mum and, therefore, is excited at a minimum when the dyno and train are in motion, and maximum when the train is at rest. This being the case, the metic attraction nioaeta of the locking magnet serves to hold the switch in an open position when the train stops, against itsbeing accidentally closed by the jars from a rough track, sudden coupling up or stoppage, nor by physical contact by the operator or others which would otherwise move the lever to contact with its litting and retaining magnet. Further, when the voltage of the battery is below normal, the attraction of the lifting coils 18 exceeds the attraction of the holding coils 29 and 30 sooner, and later, when the voltage of the battery is high, with the result that the holding magnet serves as a compensating device causing the switch to be closed sooner or later respectively when the voltage of the battery is low or high. It should here be observed that the current through this holding magnet divides between the dynamo armature and the field a larger ortion of this current passes through the old, when the coutator and brushes are loose orgued, than when clean, so that this C111. rent serves to excite the field more strongly mo when put in motion, there is avoided the loss of available current due to delay in starting the dynamo, and the preventing of excessive current when the switch closes at a high train speed and when the automatic regulator of the system is unable to act fast enou h to avoid a. heavy rush of current, the blowing of fuses and shock to the whole system including the battery.

In conclusion, it should be observed that my invention is not limited to its use between a storage battery and a dynamo for it is equally well adapted for use in connection with a gravitating contact switch connection between two dynamos or other sources or receivers of current. Nor is my invention limited to its use in connection with switch contacts operated by a gravitating lever and magnet as distinguished from any other form of movable member commonly employed for moving a switch to and maintaining it in a closed position.

Having described my invention, what I claim and desire to secure by Letters Patent is: 1. .An automatically operated switch system comprising in combination, a dynamo, a storage battery, a switch device, a movable support for the contacts thereof, an electro-magnet for holding the switch in its open position, in series circuit with the dynamo and storage battery.

2. An automatically operated switch comprising in combination switch contacts,

means for making and break ng connection we hetweensaid contacts and an electromagnet for holding the switch in open position connected across the contact posts of the switch and denergized by the contact fingers when switch is in closed osition.

3. An automatica 1y operated switch comprising in combination, switch contactposts and contact fingers, means for makingand breaking connection between said contact posts, and contact fingers, and an electromagnet for holding the switch in open position, connected across the contact posts and shunted and denergized by the contact fingers when switch is in closed position.

- In witness whereof, I have hereunto set 15 my hand and aflixed my seal this 26th day of June, A. D. 1912.

CARL EIBEHHANN.

Witnesses:

J N0. G. Emo'rr, MILDRED Emmnz. 

